This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2010/054587, filed Apr. 7, 2010, which claims the benefit of priority to Application Serial No. DE 10 2009 026 850.2, filed Jun. 9, 2009 in Germany, the disclosures of which are incorporated herein by reference in their entirety.
The disclosure relates to a valve cartridge for a magnet valve of the type claimed in independent patent claim 1, and to an associated magnet valve.
A conventional magnet valve, in particular for a hydraulic unit, which is used in an anti-lock braking system (ABS) or an anti-slip regulation system (ASR system) or an electronic stability program system (ESP system) for example, is illustrated in FIGS. 1 and 2. As can be seen from FIGS. 1 and 2, the conventional magnet valve 1, which is embodied as a control valve which is open when deenergized for example, comprises a magnet subassembly 5 for producing a magnetic flux, said assembly comprising a housing jacket 5.1, a winding carrier 5.2, a coil winding 5.3 and a covering washer 5.4, and a valve cartridge 2, which comprises a capsule 2.1, a valve core 8, a first end of which is inserted into the capsule 2.1, a magnet armature 4 having a plunger 6, and a return spring 7. In the production of the conventional magnet valve 1, the capsule 2.1 and the valve core 8 of the valve cartridge are fitted one on top of the other by pressing, and the valve cartridge 2 is sealed off hydraulically from the atmosphere by a sealing weld 2.2. In addition, the valve core 8 absorbs the pressure forces which arise in the hydraulic system and transmits them via a caulking flange 8.1 to a caulking region 41 of a fluid block 40.
When the coil winding 5.3 is energized by way of electric terminals 5.5, the magnet subassembly 5 produces a magnetic force, which moves the longitudinally movable magnet armature 4 with the plunger 6, which comprises a closing element 6.1 with a main sealing element 6.2, toward the valve core 8 against the force of the return spring 7, with the plunger 6 and the return spring 7 being guided in an internal bore of the valve core 8. The valve core 8 conducts the magnetic flux introduced via the covering washer 5.4 by the magnet subassembly 5 axially via an air gap 5.6 in the direction of the magnet armature 4. Moreover, a second end of the valve core 8 receives what is referred to as the valve body 9, which comprises a main valve seat 9.1, into which the main sealing element 6.2, which is designed as a spherical sealing cap, enters in a sealing manner in order to implement the sealing function of the magnet valve 1. In the magnet valve 1 illustrated, an integrally molded annular filter 3 having a carrier element 3.1 and a filter element 3.2 for filtering dirt particles is furthermore designed/mounted in such a way that associated sealing locations 3.3, 3.4 are arranged directly between the annular filter 3 and the magnet valve 1 in order to avoid bypasses. In this arrangement, the annular filter 3 provides an axial seal relative to the valve core 8 by way of an upper sealing location 3.3, and provides a radial seal with respect to the adjoining component, in this case a lower valve part 10, by way of a lower sealing location 3.4.
As can furthermore be seen from FIGS. 1 and 2, the lower valve part 10 is placed and supported axially against the valve core 8, said lower valve part comprising a nonreturn valve 10.1 arranged eccentrically with respect to the main valve axis and having a nonreturn valve seat 10.2 and a nonreturn valve closing element 10.3. The lower valve part 10, which is embodied as a plastic insert for example, additionally serves to provide a seal with respect to the surrounding fluid block 40, to provide a seal with respect to the valve body 9 and to receive a flat filter 11 having an inserted screen 11.2. In this arrangement, the nonreturn valve seat 10.2 is placed in the lower valve part 10, and an opening stroke 10.5 of the nonreturn valve closing element 10.3, which in this case is embodied as a ball, is limited by an abutment contour 10.4 arranged on the flat filter 11.
As can furthermore be seen from FIGS. 1 and 2, the abutment contour 10.4 for the nonreturn valve closing element 10.3 is arranged above the inserted filter screen 11.2 on the flat filter 11. Thus, either the opening stroke 10.5 of the nonreturn valve closing element 10.3 or an axial tolerance compensation length 11.4 is reduced by the dimension of a wall thickness 11.3 of the abutment contour 10.4. As a result, it is difficult to obtain optimum volume flows at the nonreturn valve 10.1 or to implement new design concepts for the magnet valve (sleeve system) with greater axial tolerance compensation possibilities. To obtain the axial tolerance compensation length 11.4, feet 11.1 of predetermined length 11.5 are formed integrally on the flat filter 11. It must be taken into account here that it is not possible to use the full length 11.5 of the flat filter feet 11.1 for axial tolerance compensation since upset material of the flat filter feet 11.1 remains in the region of tolerance compensation. The plastic flat filter 11 is connected to the adjoining lower valve part 10 in order to enable assembly and handling of the complete magnet valve 1 in production. In the magnet valve design illustrated, an annular web on the flat filter 11 enters a circumferential annular groove in the lower valve part 10. In this case, the annular web is radially compressed partially or in part in the annular groove to hold it captive.